In UdonSharpBehaviour class, the available method for OnPersistenceUsageUpdated is:

public virtual void OnPersistenceUsageUpdated()

It has no parameters, so the following documented signature cannot be overridden:

public virtual void OnPersistenceUsageUpdated(VRCPlayerApi player)

Trying to override the documented version results in a compiler error.

It would be helpful to clarify whether the no-argument version is intentional (i.e., always referring to the local player), or if the UdonSharp stub is missing the correct signature.